In providing power to an airborne vehicle, such as a missile, for example, during flight, battery packs, which are suitably charged before flight, are often used, which packs are usually relatively bulky and take up more space than is desired inside the vehicle. An alternative approach is to use a single flywheel which is activated before flight to store mechanical energy which can then be released to generate electrical energy during flight. Neither approach serves in any way to control or stabilize the roll motion of the vehicle which must be so stabilized in other ways. For example, such stabilization is often achieved merely through the use of fixedly positioned passive fins, or control surfaces, positioned at the tail end of the vehicle. Alternatively, stabilization has been achieved by designing relatively complex systems for controlling the vehicle's pitch and yaw control surfaces or by using gyroscopic control of the roll motion via appropriate control surface elements.